1. Field of the Invention
The present invention relates to liquid crystal display device, and more particularly, to AC type plasma display panel for back light capable of realizing high brightness and being free from pollution due to mercury (Hg).
2. Description of the Related Art
Compared with Cathode-ray tube (CRT), a liquid crystal display device generally has advantages of light weight, thin thickness and low power consumption and therefore, it has been substituted for the CRT in a terminal of information system and video unit, etc. And recently, the liquid crystal display device has realized wide viewing angle and is prevented a color shift, thereby obtaining high quality screen. Therefore, it is widely used in a notebook PC and a computer monitor market. In addition, it is used in TV.
The liquid crystal display device cannot emit light by oneself differently from the CRT, so that back light unit is additionally included therein as a light source. The back light unit comprises a lamp as a practical light source, a light guide plate and a plurality of optical sheets, wherein the lamp is generally a fluorescent lamp.
However, there are limitations in employing the fluorescent lamp using mercury (Hg) due to pollution problem. Moreover, it is required that the light guide plate have a predetermined thickness in order to improve uniformity and brightness of light from the fluorescent lamp, so that the light guide plate functions as a cause increasing the thickness of liquid crystal display device. As a result, it is difficult to use the conventional back light unit having the above structure as the light source in the future.
Therefore, it has been proposed a technique that plasma display panel is used as a light source in order to prevent pollution due to Hg and to decrease the thickness of liquid crystal display device.
The plasma display panel is a kind of display devices and generally has a complicated structure. However, as shown in FIGS. 1 to 3, the plasma display panel for back light has a structure that a rear substrate 2 and a front substrate 4 comprising a pair of discharge electrodes 3a, 3b, 3c are sealed by seal paste 5 with discharge gas (not shown) filled. Herein, FIG. 1 shows an opposite discharge type plasma display panel and FIGS. 2 and 3 show surface discharge type plasma display panel.
The conventional plasma display panel for back light has advantages of realizing thin thickness of liquid crystal display device without pollution due to Hg. However, gas discharge is not sufficiently generated in the discharge space, thereby lowering the brightness. As a result, it is difficult to realize high quality screen in the liquid crystal display device having plasma display panel for back light.
Therefore, an object of the present invention is to provide AC type plasma display panel for back light capable of realizing high brightness.
In order to accomplish the above object, AC type plasma display panel according to the present invention comprises a rear substrate and a front substrate arranged opposite to each other with a predetermined distance; seal paste for sealing the edges of the substrates; a pair of discharge electrodes interposed between the rear substrate and the front substrate, having a plurality of holes therein and arranged with a predetermined distance from each other in a state of no contact with the substrates; and a plurality of spacers interposed between the rear substrate and discharge electrodes and between the front substrate and discharge electrodes in order to maintain distances.
The rear substrate is generally an aluminum substrate having excellent reflexibility or a glass substrate coated a reflective film. And, the front substrate is generally a glass substrate and a fluorescent layer is coated on the inner side thereof.
The discharge electrode is made of one metal plate selected from a group comprising aluminum, chrome, copper and nickel and the fabrication method thereof comprises the steps of: forming a plurality of holes in a metal plate by using a punching process; dividing the metal plate having a plurality of holes into two; forming thin dielectric layers on the surface of the divided metal plates by using an anodizing process; and fixing the metal plates between the rear substrate and the front substrate with a predetermined distance in a state of no contact with the substrates. In order to fix the pair of metal plates, outside sealing silicon rubbers having shapes of xe2x80x98⊂xe2x80x99 and xe2x80x98⊃xe2x80x99 are put in on the edges of the metal plates and then they are fixed on the rear substrate by printing.
The above objects, and other features and advantages of the present invention will become more apparent after reading the following detailed description when taken in conjunction with the drawings.